Hitachi F-ZTAT H8/3039 Series Hardware Manual page 282

Contention between TCNT Byte Write and Increment: If an increment pulse occurs in the T
or T state of a TCNT byte write cycle, writing takes priority and TCNT is not incremented. The
3
TCNT byte that was not written retains its previous value. See figure 8-63, which shows an
increment pulse occurring in the T
ø
Address
Internal write signal
TCNT input clock
TCNTH
TCNTL
Figure 8-63 Contention between TCNT Byte Write and Increment
272
state of a byte write to TCNTH.
2
TCNTH byte write cycle
T
1
TCNTH address
N
TCNTH write data
X
T T
2 3
X + 1
2
M
X